Multi-piece Intervertebral Implants

ABSTRACT

Intervertebral implants for implanting into an intervertebral space are provided. The implants can comprise one or more layers that are operably attached to one another. An implant can comprise a first layer having a first mating surface that mates with a second mating surface of a second layer. The first mating surface and the second mating surface can have features that allow them to complement each other. The implants can include one or more bore holes for receiving a fixation member. The bore holes can be horizontal, vertical or diagonal. In some cases, the bore holes will be blind bore holes.

CROSS REFERENCE TO RELATED APPLICATIONS

This Patent Application is a continuation-in-part application of U.S.patent application Ser. No. 13/267,119, filed Oct. 6, 2011, which claimspriority to U.S. Provisional Application 61/535,726, filed on Sep. 16,2011, the entire contents of which are incorporated by reference.

FIELD OF THE INVENTION

The present invention is generally directed to intervertebral implantsand in particular, spacers for introducing into an intervertebral space.

BACKGROUND OF THE INVENTION

Spinal fusion procedures are performed to alleviate pain caused bytrauma, disc herniation or spondylosis. In some procedures, portions ofa spinal disc can be removed and replaced by an intervertebral implantdesigned to assist in the fusion process. There thus is a need forimproved intervertebral implants that can be inserted into anintervertebral space between two vertebrae.

SUMMARY OF THE INVENTION

Various embodiments of intervertebral implants are provided. In someembodiments, an intervertebral implant comprises a first layer having asuperior surface for contacting a vertebral body and a second layerhaving an inferior surface for contacting a vertebral body. The secondlayer is operably attached to the first layer. The implant furthercomprises a bore hole that extends through at least a portion of thefirst layer and the second layer, wherein the bore hole has a firstopening that opens at one of either the superior surface of the firstlayer or the inferior surface of the second layer and a second openingthat is blocked by one of either the first layer or the second layer.

In other embodiments, an intervertebral implant comprises a first layerhaving a superior surface for contacting a vertebral body and a secondlayer having an inferior surface for contacting a vertebral body. Thesecond layer is operably attached to the first layer to form asingle-bodied implant. The implant further comprises a bore hole thatextends through at least a portion of the first layer and the secondlayer, wherein the bore hole has a first opening that opens at one ofeither the superior surface of the first layer or the inferior surfaceof the second layer and a second opening that opens at a sidewall of thesingle-bodied implant formed by the first layer and the second layer.

In other embodiments, an intervertebral implant comprises a first layerhaving a first upper surface for contacting a vertebral body and a firstlower surface opposite the first upper surface. The first lower surfaceincludes one or more stepped features. The implant further comprises asecond layer having a second lower surface for contacting a vertebralbody and a second lower surface opposite the second upper surface. Thesecond upper surface includes one or more stepped features thatcomplement the first lower surface of the first layer hen the firstlayer and second layer are pressed together. In addition, the implantcomprises a bore hole that extends through at least a portion of thefirst layer and the second layer.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more readily understood with reference to theembodiments thereof illustrated in the attached figures, in which:

FIG. 1 is a front perspective view of a multi-layered implant havingflat faces and vertical bore holes formed therein according to someembodiments.

FIG. 2 is front perspective view of a multi-layered implant having flatfaces and diagonal bore holes formed therein according to someembodiments.

FIG. 3 is a top perspective view of a layer of a multi-layered implanthaving a face with a waffle pattern according to some embodiments.

FIG. 4 is a top perspective view of a complementary layer to the layerin FIG. 3 according to some embodiments.

FIG. 5 is a cross-sectional view of a multi-layered implant havinglayers with mated waffle faces according to some embodiments.

FIG. 6 is a top perspective view of a layer of a multi-layered implanthaving block features according to some embodiments.

FIG. 7 is a top perspective view of a complementary layer to the layerin FIG. 6 according to some embodiments.

FIG. 8 is a cross-sectional view of a multi-layered implant having blockfeatures and diagonal bore holes formed therein according to someembodiments.

FIGS. 9A and 9B illustrate different views of a multi-layered implanthaving layers with interlocking curved faces according to someembodiments.

FIGS. 10A-10C illustrate different views of a multi-layered implanthaving a mating interface comprising waffle-pattern features accordingto some embodiments.

FIGS. 11A-11C illustrate different views of a multi-layered implanthaving a mating interface comprising geometrical inserts according tosome embodiments.

FIGS. 12A-12C illustrate different views of a multi-layered implantincluding horizontal bore holes according to some embodiments.

FIGS. 13A-13C illustrate different views of a multi-layered implantincluding diagonal bore holes according to some embodiments.

FIG. 14 is a top perspective view of a layer of a multi-layered implanthaving receiving windows according to some embodiments.

FIG. 15 is top perspective view of a complementary layer to the layer inFIG. 14.

FIG. 16 illustrates different views of a multi-layered implant includinga layer with a mating face including angled protrusions according tosome embodiments.

FIG. 17 is a top perspective view of a layer of a multi-layered implantcomprising block features according to some embodiments.

FIG. 18 is a top perspective view of a complementary layer to the layerin FIG. 17.

FIG. 19 is a cross-sectional view of a multi-layered implant havingdiagonal bore holes formed therein.

FIGS. 20A-20D illustrate different views of an implant having teethaccording to some embodiments.

FIGS. 21A-21D illustrate different views of an alternative implanthaving teeth according to some embodiments.

FIGS. 22A-22D illustrate different views of an alternative implanthaving teeth according to some embodiments.

FIGS. 23A-23E illustrate different views of an alternative implanthaving teeth according to some embodiments.

FIGS. 24A-24E illustrate different views of an alternative implanthaving teeth according to some embodiments.

FIGS. 25A-25E illustrate different views of an alternative implanthaving teeth according to some embodiments.

FIGS. 26A-26D illustrate different views of an implant having ridgesaccording to some embodiments.

FIGS. 27A-27E illustrate different views of an alternative implanthaving ridges according to some embodiments.

FIGS. 28A-28E illustrate different views of an alternative implanthaving ridges according to some embodiments.

FIGS. 29A-29E illustrate different views of an alternative implanthaving ridges according to some embodiments.

FIGS. 30A-30F illustrate different views of an alternative implanthaving ridges according to some embodiments.

FIGS. 31A-31F illustrate different views of an alternative implanthaving ridges according to some embodiments.

FIGS. 32A-32C illustrate different views of a multi-layered implanthaving various mating features according to some embodiments.

FIGS. 33A-33C illustrate different views of an alternative multi-layeredimplant having various mating features according to some embodiments.

FIGS. 34A-34C illustrate different views of an alternative multi-layeredimplant having various mating features according to some embodiments.

FIGS. 35A-35C illustrate different views of an alternative multi-layeredimplant having various mating features according to some embodiments.

FIGS. 36A-36C illustrate different views of an alternative multi-layeredimplant having various mating features according to some embodiments.

FIGS. 37A-37C illustrate different views of an alternative multi-layeredimplant having various mating features according to some embodiments.

FIGS. 38A-38C illustrate some embodiments of a multi-piece implanthaving a pair of bore holes.

FIGS. 39A-39C illustrate some embodiments of an alternative multi-pieceimplant having a pair of bore holes.

FIGS. 40A-40C illustrate some embodiments of an alternative multi-pieceimplant having a pair of bore holes.

FIGS. 41A-41C illustrate some embodiments of an alternative multi-pieceimplant having a pair of bore holes.

FIGS. 42A-42C illustrate some embodiments of an alternative multi-pieceimplant having a pair of bore holes.

FIGS. 43A-43C illustrate some embodiments of an alternative multi-pieceimplant having a pair of bore holes.

FIGS. 44A-44C illustrate some embodiments of multi-piece implant havingan inner concentric member.

FIG. 45 is a cross-sectional view of a multi-piece implant having a pairof bore holes according to some embodiments.

FIG. 46 illustrates a multi-piece implant having concentric componentsaccording to some embodiments.

FIG. 47 illustrates a multi-piece implant having an insertable componentaccording to some embodiments.

FIG. 48 illustrates an alternative multi-piece implant having aninsertable component according to some embodiments.

FIGS. 49A and 49B illustrate different embodiments of a multi-pieceimplant having components with engaging surfaces.

FIG. 50 illustrates a multi-piece implant having a connecting platemember according to some embodiments.

FIG. 51 illustrates a multi-piece implant having threaded componentsaccording to some embodiments.

FIGS. 52A and 52B illustrate a multi-piece implant having a concentricinner member according to some embodiments.

FIG. 53 illustrates an insertable member of a multi-piece implantaccording to some embodiments.

FIGS. 54A-54C illustrate an implant having shims according to someembodiments.

FIGS. 55A and 55B illustrate an alternative implant having shimsaccording to some embodiments.

FIGS. 56A-56C illustrate an alternative implant having shims accordingto some embodiments.

FIG. 57 illustrates a shim according to some embodiments.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Embodiments of the invention will now be described. The followingdetailed description of the invention is not intended to be illustrativeof all embodiments. In describing embodiments of the present invention,specific terminology is employed for the sake of clarity. However, theinvention is not intended to be limited to the specific terminology soselected. It is to be understood that each specific element includes alltechnical equivalents that operate in a similar manner to accomplish asimilar purpose.

The present application describes intervertebral implants that areconfigured to be implanted in an intervertebral space between twovertebrae. The implants can comprise one or more spacers, cages, wedges,rings, etc. that are insertable into a disc space. The implants canremain in the intervertebral space for an extended period of time andcan assist in interbody fusion processes.

In some embodiments, the intervertebral implants comprise single-pieceor multi-piece spacers. The multi-piece spacers can include two, three,four or more layers that are placed horizontally, vertically, or in anyorientation relative to one another. The spacers can be formed of anumber of different types of materials, including various metals such astitanium and stainless steel, metallic alloys, polymers such as PEEK andcombinations thereof. In other embodiments, the spacers are formed of abone-material, either natural or synthetic. In some embodiments, thebone-material can include allograft bone, autograft bone, xenograft boneor combinations thereof. The material for such allograft spacers can betaken, for example, from a diaphysis of a long bone.

FIGS. 1-19 illustrate various embodiments of multi-piece spacers havinglayers with multiple features according to some embodiments. While thedifferent layers of material can be held together using an adhesive, inmost of the illustrated embodiments, a fixation device, such as a screw,pin or interference fit device is used to secure the layers together. Insome embodiments, the fixation device can be inserted into a bore holeformed through one or more layers of the implant.

FIG. 1 illustrates a multi-piece implant 10 comprised of two layers 12,14 of material. Each of the layers 12, 14 has a mating face 22, 24. Bothmating face 22 and 24 are illustrated as flat. When the two layers 12,14 are pressed and secured together, they form an intervertebral implantthat can be inserted into a vertebral space. In some embodiments,additional layers can be attached to layers 12, 14, thereby forming animplant with more than two layers. The advantage of having multi-pieceimplants is that the implants can be sized accurately using more or lesslayers to fit within an intervertebral space along different levels ofthe spine for patients of different sizes.

Each of the layers 12, 14 has two vertical bore holes 80, 82 formedtherein. Layer 12 has vertical bore holes 80 a, 82 a, while layer 14 hasvertical bore holes 80 b, 82 b. The vertical bore holes 80 a, 82 a inlayer 12 correspond with and align with the vertical bore holes 80 b, 82b in the other layer 14, thereby forming the two continuous bore holes80, 82 through the implant. The bore holes 80, 82 are configured toreceive a fixation device, such as a pin or screw, to secure the firstlayer 12 to the second layer 14. For purposes of this application, theterm “bore hole” can refer to a bore hole through a single layer, or acontinuous bore hole formed by multiple bore holes formed throughmultiple layers.

The bore holes 80, 82 in FIG. 1 extend from a superior face 5 (e.g., thetop surface of representative layer A) to an inferior face 6 (e.g., thebottom surface of representative layer B). Each of these faces 5, 6 areconfigured to contact a vertebral body, such as an adjacent superior andinferior vertebral body. In other embodiments, the bore holes 80, 82need not extend all the way through a superior face 5 and an inferiorface 6. For example, the bore holes can be blind bore holes, in which atleast one side of the bore hole is blocked or enclosed, as shown in FIG.32B. In other words, for a blind bore hole, at least one of the openingsis covered or enclosed. Alternatively, the bore holes can extend from atop or bottom surface into a side surface, such they will not extendcompletely through from a superior face to an inferior face, as shown inFIG. 42.

FIG. 2 also illustrates a multi-piece implant 10 comprised of two layers12, 14, of material. While the multi-piece implant 10 has flat faces, asin the previously described implant, the implant 10 in FIG. 2 includestwo diagonal bore holes 86, 88 instead of two vertical bore holes. Thetwo diagonal bore holes 86, 88 are formed from bore holes 86 a, 88 a inlayer 12 that extend continuously with the bore holes 86 b, 88 b inlayer 14. As shown in FIG. 2, the bore holes 86, 88 extend through theimplant from a superior face 5 to an inferior face 6. In otherembodiments, the bore holes can extend through an implant from aposterior face to an anterior face, or through an implant from a firstsidewall to a second sidewall.

FIG. 3 illustrates a single layer 12 of a multi-piece implant 10 havingvertical bore holes 80, 82 and a mating face 8 comprising awaffle-pattern. The vertical bore holes 80, 82 are configured to receivea fixation device for securing the layer to a second layer 14, shown inFIG. 4.

As shown in FIG. 3, the layer 12 can include a mating face 33 thatincludes a plurality of square or rectangular protrusions 38. Theprotrusions 38 form a waffle-pattern on the face 33 that is capable ofmating with a complementary face 36 of another layer 14, as shown inFIG. 4. In other embodiments, the protrusions 38 are not square orrectangular, but are of various other shapes, such as tear-shaped ortrapezoidal.

FIG. 4 illustrates a layer 14 that is complementary to the layer 12. Thelayer 14 includes a complementary face 36 that also includes square orrectangular protrusions 38. The protrusions 38 in the first layer 12 fitinto the voids formed between the protrusions 38 in the second layer 12,thereby forming an interlocking implant. In other words, the wafflepattern on the mating face 36 of layer D is configured to fit andcomplement the waffle pattern on the mating face 33 of layer C, therebyforming a two layer spacer that can be inserted into an intervertebralspace. As shown in FIGS. 3 and 4, vertical pin holes 80, 82 can extendthrough the implant 10.

The waffle pattern on the layer can mate with one or more complementarypatterns on other layers, such that two layers can be convenientlymated. As shown in FIG. 3, the waffle pattern is formed of square and/orrectangular formations that have edges. However, in other embodiments,the waffle pattern can be formed by other formations of differentgeometrical shapes, such as triangular protrusions.

FIG. 5 is a cross-sectional view of a multi-layered implant 10 havinglayers 12, 14 with mated waffle faces according to some embodiments.Layer 12 includes a mating face 33 with square or rectangularprotrusions that complements the mating face 33 of layer 14. As shown inFIG. 5, the multi-layered implant 10 includes diagonal bore holes 86, 88for receiving one or more fixation devices.

FIG. 6 illustrates a layer 12 of a multi-piece implant 10 having twovertical bore holes 80, 82. The layer in FIG. 6 includes a mating face33 having protruding features comprising multiple block features 39 inparallel to one another. Advantageously, the blocks 39 extend from oneside of the implant to another, thereby forming a mating surface that iscontinuous throughout a length of the side of the implant. While theblocks 39 are illustrated as being of similar size and evenlydistributed, in other embodiments, the blocks 39 can be of differentsize and or distributed unevenly along the length of the spacer.

FIG. 7 illustrates a layer 14 of a multi-piece implant designed tocorrespond and mate with the layer 12 in FIG. 6. The representativelayer F in FIG. 7 includes a mating face 37 having multiple blockfeatures 39 in parallel that is designed to interlock with the layer inFIG. 6. The layer in FIG. 7 also includes two vertical bore holes thatare designed to match with the vertical bore holes in FIG. 6 to form twocontinuous bore holes that extend through implant 10.

FIG. 8 illustrates a cross-sectional view of a multi-piece implant 10formed of two layers 12, 14. Each of the layers 12, 14 has a faceincluding a plurality of block features 39, as shown in FIGS. 6 and 7.The two layers 12, 14 include a pair of diagonal bore holes 86, 88 thatextend through the implant.

FIGS. 9A and 9B illustrate different views of a multi-piece implant 10formed of two interlocking layers 12, 14 according to some embodiments.Layer 12 includes a shaped “dovetail” groove 42 designed to receive acomplementary mating feature 44 protruding from a surface of layer 14.Advantageously, the mating feature 44 is curved, which helps to securelyinterlock layer 14 into layer 12, thereby forming a secure implant.

As shown in the figures, a pair of bore holes can be formed through theimplant 10. The bore holes can be vertical bore holes 80, 82, as in FIG.9A, or diagonal bore holes 86, 88, as in FIG. 9B. In other embodiments,combinations of vertical and diagonal bore holes are also possible.

FIGS. 10A-10C illustrate different views of a multi-layered implanthaving a mating interface comprising waffle-pattern features accordingto some embodiments. FIG. 10A illustrates an upper layer 12 having abottom mating face comprised of a plurality of square or rectangularprotrusions 38 with grooves in between that form a waffle-pattern. FIG.10B illustrates a lower layer 14 having an upper mating face includingsquare or rectangular protrusions 38 and grooves in between that isdesigned to complement the mating face of the upper layer 12. Themulti-layered implant can include vertical bore holes 80, 82, as shownin FIGS. 10A and 10B, or diagonal bore holes, as shown in FIG. 10C, forreceiving a fixation member.

FIGS. 11A-11C illustrate different views of one or more layers of amulti-layered implant 10 having a mating interface comprisinggeometrical inserts according to some embodiments. FIG. 11A illustratesrepresentative layer I_(b), which includes a mating face 33 having oneor more cylindrical inserts 52 protruding from a surface. Thecylindrical inserts 52 can be inserted into apertures 53 of acorresponding mating face, as shown in FIG. 11B. The cylindrical insertsadvantageously serve as pegs that help to maintain and secure themultiple layers of the multi-layered implant together before and duringimplant.

FIG. 11C illustrates an alternative layer 12 of a multi-layered implant10 having a mating interface comprising differently shaped geometricalinserts 38. The geometrical inserts 38 resemble square or rectangularfeatures (similar to that shown in FIG. 4), and can be inserted into oneor more apertures on a face of a complementary layer. As shown in FIG.11C, the layer 12 also includes one or more block features 39 thatextend along a height of the layer 12. By combining different engagingfeatures, such as the geometrical inserts 38 and the block features 39,this strengthens the ability to interlock two layers of a multi-layeredimplant, thereby helping to secure the implant during use.

FIGS. 12A-12C illustrate different views of a multi-layered implantincluding horizontal bore holes according to some embodiments. FIG. 12Aillustrates a layer 12 having one or more horizontal bore holes 94, 96that can be axially aligned with one or more horizontal bore holes 94,96 in a complementary layer 14 (shown in FIG. 12B). The mating face 33of layer 12 also comprises a plurality of channels or grooves 40 thatare designed to receive complementary features (e.g., block features 39)that protrude from the mating face 37 of layer 14.

FIG. 12C illustrates a cross-sectional view of an implant 10 having twolayers 12, 14 mated together and including horizontal bore holes 94, 96.The horizontal bore holes 94, 96 extend from an anterior side 7 to aposterior side 8 of the implant 10.

FIGS. 13A-13C illustrate different views of a multi-layered implantincluding diagonal bore holes 98, 99 according to some embodiments. Thediagonal bore holes 98, 99 extend from an anterior face 7 to a posteriorface 8. As shown in FIG. 13A, the multi-layered implant can include afirst layer 12 having a first mating face 33 including one or moregrooves for mating with a second mating face 36 of a second layer 14having one or more protruding features. Alternatively, as shown in FIG.13B, the multi-layered implant 10 can include a first layer 12 having aflat mating face 22 and a second layer 14 having a flat mating face 24that form an interface. In yet another embodiment, as shown in FIG. 13C,the multi-layered implant 10 can include a first layer 12 having a firstmating face with a block feature 39 that is capable of being insertedinto a groove 40 formed in a second mating face of a second layer 14.

FIG. 14 is a top perspective view of a layer 12 of a multi-layeredimplant 10 having receiving windows 104 according to some embodiments.The receiving windows 104 are configured to receive one or moreprotruding features from a corresponding layer (not shown).Advantageously, the windows 104 have a sufficient height and width toaccommodate a number of differently shaped protruding features. Forexample, while the windows 104 are rectangular shaped and canaccommodate complimentary rectangular features, the windows 104 can alsoaccommodate one or more cylindrical features. As shown in FIG. 14, thelayer 12 also include vertical bore holes 80, 82 and a horizontal borehole 101 that extends along a length of its longitudinal axis. Thecombination of different oriented bore holes advantageously allows forfixation members (e.g., pins) to be placed in the most desirable areasto support the mating of the different layers of the implant.

FIG. 15 is top perspective view of a complementary layer 14 to the layer12 in FIG. 14. Layer 14 includes two large rectangular inserts 106, 108that can fit within the windows 102, 104 of the layer 14. The sides ofthe inserts 106, 108 can be flush against the sidewalls of the windows102, 104. As shown in FIG. 15, layer 14 can include a horizontal borehole 94 that is aligned along a length of a width of the layer 14.

FIG. 16 illustrates different views of a multi-layered implant 10including a layer 12 with a mating face including protruding angledfeatures 111 according to some embodiments. The protruding angledfeatures 111 can fit into grooves 40 that are formed in a second layer14, thereby forming a secure implant. In some embodiments, the grooves40 are angled to complement the angled features 111. In otherembodiments, the grooves 40 are not angled and simply receive andmaintain the angled features 111 therein.

FIG. 17 is a top perspective view of a layer 12 of a multi-layeredimplant 10 comprising block features 39 according to some embodiments.The block features 39 are configured to be received in grooves 40 formedin a complementary layer 14 (shown in FIG. 18).

FIG. 18 is a top perspective view of a complementary layer 14 to thelayer in FIG. 17. Layer 14 includes a plurality of grooves 40 forreceiving the block features 39. In addition, as shown in FIG. 18, thevertical bore holes 80, 82 need not be symmetrical along the width ofthe layer 14 body. One vertical bore hole 80 extends through a groove40, while the other vertical bore hole 82 extends through a walladjacent to the groove 40.

FIG. 19 is a cross-sectional view of a multi-layered implant 10 havingtwo layers 12, 14 with diagonal, bore holes 86, 88 formed therein. Thediagonal bore holes 86, 88 extend through the interface formed by twofaces of layers 12, 14.

FIGS. 20A-31F illustrate different implants having superior and/orinferior faces with surface features, such as teeth or ribs. While suchimplants are illustrated as being single-bodied, in some embodiments,the spacers are multi-pieced and can include any of the matingfeatures/bore-holes described above. In addition, in some embodiments,the superior and inferior faces can be straight and substantiallyparallel to one another. In other embodiments, the superior and/orinferior faces can be curved (e.g., convex or concave). In addition, insome embodiments, each of the illustrated implants can have bodies thatare angled to reflect the natural lordosis in a spine. In someembodiments, the implant bodies have angles between 2 degrees and 50degrees, or 1 degree and 25, degrees relative to an axis that runsthrough the body of the implant, such as a midplane.

FIGS. 20A-20D illustrate different views of an implant 200 having teeth232 according to some embodiments. The implant 200 can be inserted, forexample, in the cervical area of a spine. The implant 200 includes aconcave surface 206 in opposition to a convex surface 204 separated by apair of sidewalls 208, 209. The implant 200 includes a superior face 216and an opposing inferior face 218, which are substantially parallel. Inother embodiments, the superior face 216 and/or inferior face 218 can becurved or angled such that the two faces are not substantially parallel.

The superior and/or inferior faces 216, 218 can include a plurality ofteeth 232 for providing a friction surface against adjacent vertebrae.In some embodiments, the teeth 232 of similar height, while in otherembodiments, the teeth 232 can have varying height across the body ofthe implant. The teeth can be three-sided, four-sided, six-sided or anyother geometrical configuration. In some embodiments, the teeth aresaw-tooth shape and include at least one surface that is substantiallyperpendicular to a surface of the implant.

A central hole 219 can be formed in the body of the implant 200 toreceive a plug 210, such as in FIG. 20B. While the central hole 219 isillustrated as being circular, in other embodiments, the central hole219 is square, rectangular, trapezoidal, tear shaped, or any othershape. In some embodiments, the central hole 219 has a geometryincluding one or more edges. In some embodiments, the implant 200 bodycan be formed of cortical material, while the inner plug 210 can beformed of cancellous material.

As shown in FIGS. 20B and 20D, the implant 200 can include one or moreslots 260 configured to be grasped by an insertion instrument. While theslots 260 are formed on the sidewalls 208, 209 of the implant 200, inother embodiments, slots 260 can be formed on other parts of the implantbody, such as on a superior 216 and/or inferior surface 218.

In addition to the features discussed above, the implant 200 can includea leading edge 240. In some embodiments, the leading edge 240 serves asdistraction surface that helps to distract one or more vertebral bodieswhile the implant 200 is inserted into a disc space. In someembodiments, the leading edge 240 comprises smooth, tooth-free zonesthat are formed on the superior 216 and/or inferior surface 218 of theimplant 200. As shown in FIG. 20D, the leading edge 240 can be angled ortapered such that the implant 200 is bullet-nose or wedge shaped.

FIGS. 21A-21D illustrate different views of an alternative implant 300having teeth 232 according to some embodiments. The implant 300 can beinserted, for example, in a lumbar region of the spine via an anteriorapproach. The implant 300 can include two convex surfaces 332, 334 withsidewalls 308, 309 formed in between. The implant 300 further includes asuperior surface 316 and an inferior surface 318. As shown in FIG. 21B,the superior surface 316 and/or the inferior surface 318 can have someslight curvature. In some embodiments, both the superior surface 316 andthe inferior surface 318 include one or more teeth 232 to assist inproviding a frictional zone against adjacent vertebral bodies.

As shown in FIG. 21A, the implant 300 can include a central hole 319.Unlike the central hole 219 in FIG. 20B, the central hole 319 in thepresent implant 300 is not filled with a cancellous bone plug. In someembodiments, the central hole 319 can be configured to receive bonegraft material, which can assist in spinal fusion in between twovertebrae.

In some embodiments, the implant 300 can also include a leading edge 340which is formed at the convergence of the superior surface 316 andinferior surface 318. The leading edge 340 can comprise smooth,tooth-free zones that serve to advantageously distract vertebral bodiesduring implantation. As shown in FIG. 21B, leading edge 340 can beangled such that a portion of the implant 300 is bullet-nosed or wedgeshaped.

In some embodiments, the implant 300 can also include slots 324 that areformed on the superior and/or inferior surfaces 316, 318 of the implant.In some embodiments, an insertion instrument can be used to grip theslots 324, thereby helping to facilitate the insertion of the implant ina vertebral space. In other embodiments, the slots 324 can receive oneor more portions of a distraction instrument to assist in thedistraction of adjacent vertebrae during implantation. In someembodiments, the insertion instrument can be an instrument separate froma distraction instrument. In other embodiments, the insertion instrumentcan include a distractor function, and can advantageously distractvertebrae while simultaneously inserting an implant.

FIGS. 22A-22D illustrate different views of an alternative implant 400having teeth 232 according to some embodiments. The implant 400 can beinserted, for example, in a lumbar region of the spine via atransforaminal approach. The implant includes a superior surface 416 andan inferior surface 418 that include teeth 232. As shown in FIG. 22A,the teeth need not extend entirely across the body of the implant 400;rather, a tooth-free region can be formed around the teeth 232. Theimplant 400 can include a convex surface 404 opposite a concave surface406. The convex surface 404 and concave surface 406 can be substantiallyparallel, while in other embodiments, the convex surface 404 and concavesurface 406 are not substantially parallel. As shown in FIG. 22C, theimplant 400 can have a rectangular cross-sectional area.

In some embodiments, the implant 400 can include a slot 260. The slot260 can be formed on the convex surface 404 and or concave surface 406,and can be configured to receive an insertion instrument to assist indelivery of the implant into an intervertebral space. In addition, as inpreviously discussed implants, the implant 400 can include a tooth-free,leading edge 440.

FIGS. 23A-23E illustrate different views of an alternative implant 500having teeth according to some embodiments. The implant 500 can beinserted, for example, in a lumber region of the spine via a posteriorapproach. The implant 500 can have a substantially flat superior surface516 that opposes a substantially flat inferior surface 518. In someembodiments, the implant 500 can be flat in a medial-lateral direction,but can include a radius of curvature in the anterior-posteriordirection. Each of the superior surface 516 and/or inferior surface 518can include teeth 232 for contacting vertebral bodies. As shown in FIG.23C, the implant 500 can also include a leading edge 540.

As shown in FIGS. 23B and 23C, the implant 500 can include a large slot560 for receiving a portion of an insertion instrument. In someembodiments, the slot 560 advantageously extends along a majority of thelength of the implant 500, thereby creating a large surface area forreceiving a portion of an insertion instrument.

FIGS. 23D and 23E illustrate alternative rear views of the implant 500.As shown in these figures, in some embodiments, a posterior portion ofthe implant 500 can have angled, tapered surfaces 582 that converge at aflat face 590. In some embodiments, the posterior face 590 can have alength and height that is substantially different from the length andheight of a face along an anterior portion of the implant 500.

FIGS. 24A-24E illustrate different views of an alternative implant 600according to some embodiments. The implant 600 can be inserted, forexample, in a lumbar region of the spine via a posterior approach. Theimplant 600 shares many similar features as the implant in FIG. 23A,including a superior face 616 and inferior face 618 including teeth 232,a leading edge 640 that is angled, and a slot 660 that extendssubstantially along a majority of the length of the body of the implant600.

FIGS. 25A-25E illustrate different views of an alternative implant 700having teeth 232 according to some embodiments. The implant 700 can beinserted, for example, in a lumbar region of the spine via a lateralapproach. The implant includes a superior face 716 and an inferior face718, each including a plurality of teeth 232 formed thereon. As shown inFIG. 25C, the superior face 716 and inferior face 718 can besubstantially flat and planar, while in other embodiments, the superiorface and/or inferior face can be curved. The implant 700 can alsoinclude a tooth-free, leading edge 740.

In some embodiments, the implant 700 can include a hole 719 extendingfrom a superior face 716 to an inferior face 718, as shown in FIG. 25A.While the hole 719 is illustrated as a polygon having one or more curvedor straight edges, in other embodiments, the hole 719 is round. As shownin FIG. 25A, the hole 719 can include two sidewalls 722 and 723 thatextend along a majority of the length of the implant 700. By having sucha lengthy hole, bone graft can advantageously be inserted and grow alonga substantial portion of the implant, thereby aiding in bone fusionprocesses. In some embodiments, the two sidewalls 722, 723 substantiallymatch the sidewalls of the implant 700.

In some embodiments, as shown in FIG. 25E, implant 700 can include oneor more slots 724 on a superior surface 716 and/or inferior surface 718.The slots 724 can be configured to receive one or more instruments, suchas insertion or distraction instruments, to assist in the implantationof the implant 700.

In contrast to the implants in FIGS. 20A-25E, the implants in FIGS.26A-31F include ribs or ridges, rather than teeth. These implants arenow discussed.

FIGS. 26A-26D illustrate various embodiments of an implant 1200 havingridges 236. The implant 1200 can be inserted, for example, in a cervicalregion of the spine. The implant 1200 can include a convex surface 204and a concave surface 206 with sidewalls therebetween.

The implant 1200 can include a plurality of ridges 236 formed on asuperior surface 216 and/or inferior surface 218. In some embodiments,the ridges 236 are formed continuously across a surface of the implant1200 (as shown in FIG. 26A), whereas in other embodiments, the ridges236 are separated and have spaces in between. The implant 1200 caninclude a tapered leading edge 240, thereby forming a bullet-nose orwedge-shaped portion.

In some embodiments, as shown in FIG. 26B, the convex surface 204 cancomprise a posterior face having a height H2. The concave surface 206can also comprise an anterior face having a similar height H2. Oneskilled in the art will appreciate that the convex surface 204 can alsobe considered an anterior face, while the posterior face can beconsidered an anterior face, depending on the position of a userrelative to the spine. In other embodiments, the anterior face andposterior face of the implant 1200 can be of differing heights.

FIGS. 27A-27E illustrate various embodiments of an alternative implant1300 having ridges 236. The implant can be inserted, for example, in alumbar region of the spine via an anterior approach. The implant 1300includes a superior surface 1316 and an inferior surface 1318, eachcovered in part by one or more ridges 236. As shown in FIG. 27A, theimplant 1300 can include a leading end 1340 which is smooth and notcovered by ridges. In addition, the implant 1300 can include one or moreslots 1324 that can be grasped by a distraction and/or insertioninstrument to assist in inserting the implant into a vertebral space.The implant 1300 also includes a hole 1319 for receiving graft material.While the hole 1319 is illustrated as circular, in other embodiments,the hole 1319 is square, rectangular, trapezoidal or any other shape.

In some embodiments, as shown in FIG. 27B, the superior surface 1316 andthe inferior surface 1318 are substantially parallel. In otherembodiments, the superior surface 1316 and/or the inferior surface 1318can be partially curved and/or angled (lordotic), such that the twosurfaces are not substantially parallel. In some embodiments, ananterior face of the implant 1300 can be of similar height H2 to aposterior face of the implant 1300, as shown in FIG. 27B.

As shown in FIG. 27D, the ridges 236 formed on the implant can besubstantially continuous. That is, there is a minimal if any gap orspace between adjacent ridges. In other embodiments, the ridges 236 canbe separated by a space and are not continuously formed.

FIGS. 28A-28E illustrate various embodiments of an alternative implant1400 having ridges 236 that can be used, for example, in a lumbar regionvia a transforaminal approach. The implant 1400 includes a firstsidewall 1404 that is opposite a second sidewall 1406. The firstsidewall 1404 includes two concave surfaces 1414 and 1418. The secondsidewall 1406 includes a third concave surface 1406. Advantageously,with the multiple concave surfaces, the implant 1400 is of a geometrythat is desirable for different approaches, such as a transforaminalapproach.

In addition to the features discussed above, the implant 1400 can alsoinclude one or more slots 1460 formed on one or more of the sidewalls1404, 1406. The one or more slots 1460 can be grabbed by an insertioninstrument.

FIGS. 29A-29E illustrate various embodiments of an alternative implant1500 having ridges 236 that can be used, for example, in a lumbar regionof the spine via a posterior approach. The implant includes a pair ofside channels 1560 for receiving an insertion instrument Advantageously,as shown in FIG. 29A, the side channels 1560 can extend along a majorityof the length of the implant 1500, thereby providing a large graspingarea for the insertion instrument.

FIGS. 30A-30F illustrate various embodiments of an alternative implant1600 having ridges 236 that can be used, for example, in a lumbar regionof the spine via a posterior approach. The implant is similar to thatshown in FIGS. 29A-29E, but includes a different footprint. While someof the embodiments illustrate an implant 1600 having a superior surface1616 and an inferior surface 1618 that are parallel or minorly curved(FIG. 30B), other embodiments illustrate an implant 1600 having asuperior surface 1616 and an inferior surface 1618 that are noticeablycurved and form a lordotic structure (FIG. 30F).

FIGS. 31A-31F illustrate various embodiments of an implant 1700 havingridges 236 that can be used, for example, in a lumbar region via alateral approach. In some embodiments, the implant can include twoparallel sidewalls 1706 and 1708 (FIG. 31A), while in other embodiments,the implant can include a straight sidewall 1706 that opposed a convexsidewall 1708 (FIG. 31E). In addition, in some embodiments, the implant1700 can have substantially parallel superior and inferior surfaces1716, 1718 (FIG. 31D), while in other embodiments, the implant 1700 canhave a lordotic angled surface (FIG. 31F).

FIGS. 32A-44 illustrate additional embodiments of multi-piece implantassemblies. These embodiments are now described and are meant only to beillustrative. For example, while the implant assemblies in FIGS. 32A-44do not illustrate horizontal bore holes, these implants may also includethese features.

FIGS. 32A-32C illustrate embodiments of a multi-piece implant 10 havingangled and/or curved mating faces 27, 28. Layer 12 includes an angledmating face 27 that mates with angled mating face 28 of layer 14.Advantageously, by having complementary features, this helps to keep thetwo layers 12, 14 of the implant 10 together.

As shown in FIGS. 32B, diagonal bore holes 86 and/or vertical bore holes80 can be introduced through the implant 10. The bore holes can extendcomplete through the implant, from a superior surface to an inferiorsurface. Alternatively, the bore holes can be blind, wherein a side ofthe bore hole is blocked by a surface of one of the layers 12, 14. Byhaving blind bore holes, this advantageously prevents inadvertentremoval or back-out of fixation members that are inserted through theholes.

FIGS. 33A-33C illustrate some embodiments of a multi-piece implant 10having zig-zagged mating faces 27, 28. Layer 12 includes a firstzig-zagged mating face 27, while layer 14 includes a second zig-zaggedmating face 28. As shown in FIG. 33C, each of the zig-zagged matingfaces 27, 28 can include stepped features. The zig-zagged mating faces27 and 28 complement each other, thereby helping to form a securemulti-piece implant.

As shown in FIG. 33B, the implant 10 can also include diagonal boreholes 86 and/or vertical bore holes 80 that extend across the interfaceof the two bodies 12 and 14. The bore holes 86 and 88 can extendcompletely through a superior surface to an inferior surface, oralternatively, can be blind bore holes as discussed above.

FIGS. 34A-34C illustrate some embodiments of a multi-piece implant 10having curved mating faces 27, 28. As shown in the figures, the matingfaces 27, 28 of the layers can be continuously curved without having anyparticular edge. The layers 12, 14 in the present embodiments can alsoinclude diagonal and/or vertical bore holes that are may or may not beblind.

FIGS. 35A-35C illustrate some embodiments of a multi-piece implant 10having straight, jagged mating faces 27, 28. As shown in FIG. 35C, layer12 can have a mating face 27 that is comprised of a single jagged step.Likewise, layer 14 can have a mating face 28 that is comprised of acomplementary jagged step such that when layer 14 is pressed againstlayer 12, the two layers form a multi-piece implant. As in previouslydiscussed embodiments, the implant 10 can include a variety of differentbore holes that are continuous from a superior surface to an inferiorsurface, or blind.

FIGS. 36A-36C illustrate some embodiments of a multi-piece implant 10having at least three layers 12, 14, 15 with flat mating faces. Layer 12includes a flat mating face 27 that forms an interface with flat matingface 28 of layer 14, while layer 15 includes a flat mating face 30 thatforms an interface with flat mating face 29 of layer 14. In otherembodiments, less than three layers (e.g., two) or greater than threelayers (e.g., four or five) having flat mating faces can form a similarmulti-piece implant.

As shown in FIG. 36B, the multi-piece implant 10 can incorporate a borehole such as vertical bore hole 80. In some embodiments, the bore hole80 will not extend through either a superior face or an inferior face,but rather, can have two blind ends, as shown in FIG. 36B.Advantageously, by having two blind ends, the bore hole 80 will be ableto fix the multiple layers together, but will be prevented frominadvertently backing out of the implant during use.

FIGS. 37A-37C illustrate some embodiments of a multi-piece implant 10having layers with mating faces 27, 28 including a pair of exteriorflats followed by a curved inner surface. As shown in FIG. 37A, layer 12can include a mating face having a pair of exterior flats 31 and acurved inner surface 32 there between. Layer 14 can include a matingsurface 28 that is complementary to the mating face 27, wherein it alsoincludes flats and a curved inner surface. The multi-piece implant caninclude diagonal and vertical bore holes of different variations asshown in FIGS. 37B.

FIGS. 38A-38C illustrate some embodiments of a multi-piece implant 10having a pair of bore holes 80, 82. As shown in FIG. 38B, each of thebore holes 80, 82 is blind. Accordingly, from a top view, only one borehole 80 is visible in the superior surface, as shown in FIG. 38A. Thebores 80, 82 each cross the interface formed by the contacting matingfaces 27 and 28.

FIG. 38B illustrates a cross-sectional view of the implant 10 accordingto some embodiments. As shown in this view, the interface between thelayer 12 and layer 14 is a flat surface. However, in alternative views,as show in the cross-sectional view of the implant 10 in FIG. 38C, theinterface between layer 12 and layer 14 can also be curved in someportions.

FIGS. 39A-39C illustrate some embodiments of an alternative multi-pieceimplant 10 having a pair of bore holes 80, 82. As shown in FIG. 39B,each of the bore holes 80, 82 is blind. Accordingly, from a top view,only one bore hole 82 is visible in the superior surface, as shown inFIG. 39A. The bores 80, 82 each cross the interface formed by thecontacting mating faces 27 and 28.

FIG. 39B illustrates a cross-sectional view of the implant 10 accordingto some embodiments. As shown in this view, the interface between thelayer 12 and layer 14 is not only flat, but also includes somecurvature. The curved features of the interface are also shown in FIG.39C.

FIGS. 40A-40C illustrate some embodiments of a multi-piece implant 10having a pair of bore holes 80, 82. The implant 10 is composed of twolayers 12, 14. Each of the layers has a mating face 27, 28 that has ahorizontally straight portion and a vertically straight portion, asshown in FIG. 40B. From a different cross-sectional view shown in FIG.40C, the mating interface between layer 12 and layer 14 is flat.

FIGS. 41A-41C illustrate some embodiments of a multi-piece implant 10having a pair of bore holes 80, 82. The implant is composed of twolayers 12, 14, each having a flat mating face 27, 28. The implant 10includes two vertical bore holes 80, 82.

FIGS. 42A-42C illustrate some embodiments of a multi-piece implant 10having a pair of diagonal bore holes 86, 88. Both of the bore holes 86,88 are blind in that they do not extend completely through an implant.The implant 10 includes two layers 12, 14 having flat mating faces 12,14, as shown from different viewpoints in FIGS. 42B and 42C.

FIGS. 43A-43C illustrate some embodiments of a multi-piece implant 10having a pair of diagonal bore holes 86, 88. In contrast to the previousembodiment, the current embodiment includes two layers 12, 14 having amating interface that is angled, as shown in FIG. 43B. In addition, insome embodiments, portions of the mating interface can be curved, asshown in FIG. 43C.

FIGS. 44A-44C illustrate some embodiments of a multi-piece implant 10having an inner concentric member 97. As shown in FIG. 44A, the implant10 is comprised of two separate layers 12 and 14. Each of the layers 12and 14 includes an inner hole that aligns to form a single through holewhen the two layers are pressed together, as shown in FIG. 44C. An innerconcentric member 97 can be received through the single through hole,thereby advantageously helping to hold the implant in one piece. Thisdesign advantageously avoid the use of fixation members (e.g., pins),which can protrude from the body of the implant and/or inadvertentlycome loose within the system. In other embodiments, fixation members canbe incorporated into the design.

FIG. 45 is a cross-sectional view of a multi-piece implant 10 having apair of bore holes 86, 88 according to some embodiments. As shown in theillustration, the multi-piece implant 10 is composed of two layers 12,14, each of which includes a v-shaped mating face 27, 28.

FIG. 46 illustrates a multi-piece implant 10 having concentriccomponents 1810, 1820 according to some embodiments. The implant 10includes a first concentric outer member 1810 and a second concentricinner member 1820 that fits therein. In some embodiments, the innermember 1820 is slidable within the outer member 1810, thereby forming animplant for implanting in an intervertebral space.

FIG. 47 illustrates a multi-piece implant 10 having an insertablecomponent 1920 according to some embodiments. The implant 10 comprises afirst layer 1910 including a slot 1927 that extends along a substantialportion of its width. The slot 1910 is configured to receive a secondinsertable layer 1920 that fits therein, thereby forming a multi-pieceimplant for implanting in an intervertebral space.

FIG. 48 illustrates an alternative multi-piece implant 10 having aninsertable component 2020 according to some embodiments. The implant 10comprises a first member 2010 that includes an open chamber 2017. Theopen chamber 2017 includes one or more slots or recesses 2019 formedtherein to receive an insertable component 2020. As shown in the figure,the insertable component 2020 can comprise a planar structure that isslidable into a corresponding recess 2019. While the illustratedembodiment shows a chamber 2017 having a single recess 2019corresponding to a single insertable component 2020, in otherembodiments, the chamber 2017 can include more than one slot. In someembodiments, the insertable component 2020 can be pinned to the openchamber 2017, thereby helping to further secure the multi-piece implantfor use.

FIGS. 49A and 49B illustrate different embodiments of a multi-pieceimplant 10 having components with engaging surfaces. FIG. 49Aillustrates two separate multi-piece implants 10 having components withengaging surfaces. Dashed lines represent optional pin holes. In someembodiments, the implant 10 can include a first component 2112 having acut corner that engages a second component 2114 having a different cutcorner to form a single-bodied implant. In other embodiments, theimplant 10 can include a first component 2112 having a cut corner, asecond component 2114 having a different cut corner, and a thirdcomponent 2116 that completes the form implant 10.

FIG. 49B illustrates an embodiment of a multi-piece implant 10 havingtwo separate components. The first component 2114 includes a cutrectangular corner, while the second component 2112 comprises a geometrythat fits within the cut rectangular corner of the first component 2114.

FIG. 50 illustrates a multi-piece implant 10 having a connecting platemember 2216 according to some embodiments. The implant 10 can comprisetwo cylindrical members 2210 and 2212. In alternative embodiments, themembers 2210 and 2212 need not be cylindrical, but can be square,rectangular or any other shape. Each of the members 2210, 2212 includeapertures 2213, 2214 for receiving a peg or rod of a connecting platemember 2216. The connecting plate member 2216 advantageously helps tohold the two cylindrical members 2210 and 2212 together, thereby formingan implant that is implantable in a vertebral space.

FIG. 51 illustrates a multi-piece implant 10 having threaded componentsaccording to some embodiments. The implant 10 can comprise a firstcomponent 2312 having an inner threaded section 2322 and a secondcomponent 2324 having a threaded protrusion 2324 that complements theinner threaded section 2322. The threaded components advantageously holdthe implant together prior to, during and after implantation of theimplant 10 in an intervertebral space.

FIGS. 52A and 52B illustrate a multi-piece implant having a concentricinner member according to some embodiments. FIG. 52A illustrates across-sectional view of an implant 10 having a concentric inner member2408 that fits in an outer member 2414, while FIG. 52B shows a top viewof the same implant 10. As shown in FIG. 52B, the outer member 2414includes a central opening for receiving the inner member 2408, whichresembles a ring. One or more bore holes can be formed through the innerand outer members to receive fixation devices for holding the implanttogether. While the bore holes are illustrated as diagonal bore holes86, 88, 96, 98, in other embodiments, vertical and/or horizontal boreholes can be used to receive fixation devices.

FIG. 53 illustrates an insertable member 2515 of a multi-piece implantaccording to some embodiments. The insertable member 2515 resembles ahorse-shoe shape that can be received, for example, in a slot formed ina receiving member (not shown). As shown in this embodiment, variousinserts of different shapes, geometries and sizes can be used to form amulti-layer implant.

FIGS. 54A-54C illustrate an implant having shims according to someembodiments. The implant 10 comprises a body having an opening 2608configured to receive one or more shim members 2611 therein. The implantcan be sized and configured for use in any part of the vertebrae,including the lumbar, thoracic, and particularly, the cervical region.

The implant 10 comprises a body having an opening 2608 that isconfigured to receive bone material therein. The implant 10 can be asingle-piece, or as in prior multi-piece implants described above, theimplant 10 can include multiple layers. In some embodiments, the implantcomprises a first layer 12 and a second layer 14. In other embodiments,the implant can be composed of three, four, five or more layers. Inaddition, while the layers 12 and 14 are stacked vertically, in otherembodiments, the layers can be assembled horizontally or laterally.

As shown in FIGS. 54A-54C, the implant 10 can have a convexly curvedanterior surface 7 and a concavely curved posterior surface 8. Suchcurvature can advantageously help to mimic the natural curvature of thespace. In some embodiments, the convexly curved anterior surface 7 canhave a curvature that is substantially smooth. In other embodiments, asshown in FIG. 54A, the curvature can include flat segments and evenslight edges, so long as the overall surface is substantially curved.One skilled in the art will appreciate that the shape of the implant isnot limited to the convexly curved anterior surface and concavely curvedposterior surface. For example, in some embodiments, the implant 10 willhave a convex surface opposed to a convex surface, or a convex surfaceopposed to a substantially flat surface. In addition, one skilled in theart will appreciate that the terms “anterior” and “posterior” are notlimiting, and that the terms can be used to identify any opposingsurface of the implant.

In some embodiments, the opening 2608 of the implant 10 extends from anupper superior surface to a lower superior surface of the implant. Insome embodiments, the opening 2608 is composed of a first openingthrough the first layer 12 and a second opening through the second layer14. In the illustrated embodiments, a first opening in the first layer12 and a second opening through the second layer 14 can be substantiallyaligned to form the opening 2608. In other embodiments, a first openingin the first layer 12 and a second opening through the second layer 14can be partially aligned and partially off-set.

As shown in FIGS. 54A and 54B, the opening 2608 in the implant 10 issymmetric, and includes a pair of opposing flat surfaces that transitioninto rounded corners. Advantageously, the rounded portions of theopening 2608 are configured to receive one or more shim members 2611therein. While the illustrated embodiments show two shim members; theimplant 10 can also be used with a single shim member, or three, four,five or more shim members.

The shim members 2611 are wedge-like members that are configured to beinserted (e.g., via friction or press-fit) through the opening 2608.Advantageously, insertion of the shim members 2611 into the opening 2608helps to maintain the different layers 12 and 14 together and furtherprovides structural support to the overall implant. In some embodiments,the shim members 2611 are oval or elliptical in shape, although othershapes and geometries are also possible. In addition, as shown in theshim member represented in FIG. 57, the shim members 2611 can include asmall nub or protrusion 2613 that extends outwardly from a generallysmooth, curved surface. The advantage of this nub 2613 is that it allowsthe shim to be more easily retained within the opening 2608 of theimplant 10. In some embodiments, the shim members 2611 are composed ofthe same or similar material as the body of the implant 10. For example,the body of the implant 10 and the shim members 2611 can all be composedof allograft (e.g., cortical) bone. In other embodiments, the shimmembers 2611 are composed of a different material from the body of theimplant 10. For example, the body of the implant 10 can be composed of acortical bone, while the shim members 2611 can be composed of a hardersynthetic material.

In some embodiments, the opening 2608 can be configured to receive theshim members 2611 at an angle relative to an interface of the firstlayer 12 and the second layer 14, as shown in FIG. 54C. Advantageously,by having shim members 2611 that are at an angle to an interface of thefirst layer and the second layer, this can help provide additionalsecurity for securing the first layer to the second layer duringimplantation. However, one skilled in the art will appreciate that theshim members 2611 can also be provided parallel or perpendicular to theinterface of the first layer and the second layer.

FIGS. 55A and 55B illustrate an alternative implant having shimsaccording to some embodiments. The implant 10 is similar to the implantshown in FIG. 54A, but also includes a plurality of ridges 236 onsuperior and/or inferior surfaces thereof. The ridges 236 advantageouslyhelp to grip adjacent vertebral surfaces. As shown in the illustratedembodiments, the ridges 236 can formed on both the body of the spacer10, as well as on the surfaces of the shim members 2611. In alternativeembodiments, the body of the spacer 10 includes ridges, while the shimmembers 2611 do not include ridges. In some embodiments, as shown inFIG. 55B, the ridges 236 can be separated by a planar surface such thatthey are maintained a certain distance from one another. In otherembodiments, as shown in FIG. 56B, the ridges 236 are not separated by aplanar surface between one another. Rather, the ridges 236 arecontinuously formed and in general, do not extend from a planar surface.While the illustrated embodiments show surface texture comprised ofridges, other types of surface texturing can also be provided, includingprotrusions, teeth, and peg members.

FIGS. 56A-56C illustrate an alternative implant having shims accordingto some embodiments. The implant 10 is similar to that shown in FIG.55A, but includes ridges 236 that are not spaced from one another. Theridges 236 in FIG. 56A thus do not extend from a planar surface, butrather are continuously formed across the superior and/or inferior facesof the implant 10. In contrast to the ridges in FIG. 55A that extendfrom a substantially planar surface, in the embodiment in FIG. 56A, theridges themselves comprise the superior and/or inferior surfaces. Inother words, there is no clear planar or base surface from which theridges extend. In some embodiments, the entire superior and/or inferiorfaces of the implant 10 are covered in ridges or some type of surfaceprotrusion. In other embodiments, and as shown in the figures, theridges 236 need not extend across the entire superior and/or inferiorsurfaces, thereby allowing for a ridge-free portion on the surfaces. Insome embodiments, the ridge-free portions of the implant 10 canadvantageously be grasped by an instrument, such as an insertioninstrument, to facilitate insertion or can be used as a distraction end.

In addition, as shown in FIG. 56B, the implant 10 further includes oneor more instrument gripping side channels 2660. In some embodiments, theone or more side channels 2660 comprise a recess having walls withoutadditional openings therein. In other embodiments, the side channels2660 comprise a recess having walls that include additional openings(e.g., scalloped openings) formed therein. Advantageously, an insertioninstrument can be used to grip the one or more side channels, therebyhelping to deliver the implant into a desired surgical space.

Additional Characteristics

In addition to those features discussed above, additional features arenow described. Any combination of features are possible to include inthe implants discussed above.

In some embodiments, the implants can be formed of allograft, xenograft,synthetic material or combinations thereof. Specific materials possiblefor use include cortical bone, cancellous bone, cortico-cancellous bone,collagen, PEEK, titanium, stainless steel, PLA, PLDL and othermaterials.

In some embodiments, the implants are formed monolithically. In otherembodiments, the implants are multi-piece, and are composed of two ormore layers. The layers can be generally planar; however, in someembodiments, the multi-piece implant can include non-planar components.For example, an implant can comprise a first portion comprised of asquare block member with a square hole formed therein and a secondportion that is capable of filling in the hole.

The implants can be incorporated in multiple levels of the spine. Forexample, the implants described above can be suited for use in thecervical, thoracic and lumbar regions of the spine.

In some embodiments, the implants have substantially planar superior andinferior surfaces that are parallel and are not lordotic. In someembodiments, these implants can have anterior and posterior sides ofsimilar height. In other embodiments, the implants have a degree oflordosis, such as up to 20 degrees with respect to a midplane. In someembodiments, these lordotic implants can have curved edges and/or curvedupper/lower sides.

The implants described above can include a mid-plane that extends alength between a superior surface and an inferior surface. In someembodiments, the superior surface and inferior surface are parallel tothe mid-plane. In other embodiments, only one of the superior surfaceand inferior surface are parallel to the mid-plane. And in anotherembodiment, neither the superior surface nor the inferior surface areparallel to the mid-plane.

The implants discussed above can have anterior, posterior and sidewallsof various shapes. For example, the walls can be curved, planar andangled.

For multi-layered implants composed of two or more layers, variousinterfaces can be formed between the implants. For example, the implantcan include a mating face interface that is flat, curved, slanted,waffle-patterned, dovetail-patterned, t-shaped, lego, textured, or anyother shape.

In some embodiments, the superior and/or inferior faces can includeroughened surfaces. The roughened surfaces can include teeth, ribs,ridges, or any other types of surface protrusion. Among the surfacesthat can include three-sided teeth, four-sided teeth, five-sided teeth,six-sided teeth and more, ridges, conical protrusions, saw teeth,pyramidal teeth and simple textures. In some embodiments, the tip of thesurface protrusions can be rounded, sharp, flat, blunt or concave.

The implants can include a number of different insertion features. Amongthe insertion features include parallel slots, converging slots,dimples, channels, nubs, holes (threaded) and holes (non-threaded).These insertion features can be located in one or more places of theimplant body, including into the body of the implant, along side walls,or on superior and inferior surfaces.

In some embodiments, the implants can include one or more graft holes.The graft holes can be of various shapes, including circular,triangular, square, oval tear-drop, tapered, trapezoidal andrectangular. In some embodiments, the graft holes have a length that isgreater than the width of adjacent walls, while in other embodiments,the graft holes have a length that is less than the width of adjacentwalls. The graft holes can be placed in a number of positions, such ascentrally, offset in an anterior-posterior direction, offset in amedial-lateral direction, or offset diagonally. In some embodiments, thegraft hole can be formed of two or more holes that are aligned, while inother embodiments, the graft hole can be formed of two or more holesthat overlap but may be axially offset from one another.

While the invention herein disclosed has been described by means ofspecific embodiments and applications thereof, numerous modificationsand variations can be made thereto by those skilled in the art withoutdeparting from the scope of the invention.

What is claimed is:
 1. An intervertebral implant for implantation in anintervertebral space comprising: a superior surface configured tocontact an upper vertebra, wherein the superior surface includes aplurality of surface protrusions; an inferior surface configured tocontact a lower vertebra, wherein the inferior surface includes aplurality of surface protrusions; an opening extending through thesuperior surface and the inferior surface; and one or more shim membersextending through the opening.
 2. The implant of claim 1, wherein thesuperior surface comprises a plurality of ridges.
 3. The implant ofclaim 1, wherein the inferior surface comprises a plurality of ridges.4. The implant of claim 1, wherein the implant is formed at least inpart by allograft bone material.
 5. The implant of claim 1, wherein theopening comprises at least one flat surface adjacent a curved surface.6. The implant of claim 1, wherein the superior surface is parallel tothe inferior surface.
 7. The implant of claim 1, wherein the superiorsurface is curved and/or angled relative to the inferior surface.
 8. Anintervertebral implant for implantation in an intervertebral spacecomprising: a first layer having a superior surface configured tocontact an upper vertebra; a second layer having an inferior surfaceconfigured to contact a lower vertebra, wherein the first layer is incontact with the second layer; and an opening extending through thefirst layer and the second layer, wherein the opening includes at leastone planar surface that transitions into a rounded portion.
 9. Theimplant of claim 8, further comprising at least one shim member forinserting into the opening.
 10. The implant of claim 9, wherein the atleast one shim member is formed of a different material from a body ofthe implant.
 11. The implant of claim 9, wherein the at least one shimmember is formed of a same material as a body of the implant.
 12. Theimplant of claim 8, wherein the at least one shim member is placed at anangle to an interface between the first layer and the second layer. 13.The implant of claim 8, wherein the at least one shim member is placedparallel or perpendicular to an interface between the first layer andthe second layer.
 14. The implant of claim 8, wherein the superiorsurface of the first layer includes a plurality of ridges continuouslyformed without a space in between one another.
 15. An intervertebralimplant for implantation in an intervertebral space comprising: a firstlayer having a superior surface for contacting a vertebral body; asecond layer having an inferior surface for contacting a vertebral body,wherein the second layer is in contact with the first layer; an openingextending through the first layer and the second layer; and at least oneshim member received in the opening, wherein the shim member isconfigured to maintain the first layer in connection with the secondlayer, and wherein the shim member is positioned at an angle that isnon-perpendicular to the interface of the first layer and the secondlayer.
 16. The implant of claim 15, wherein a body of the implantincludes a convexly curved anterior surface and a concavely curvedposterior surface.
 17. The implant of claim 15, wherein the shim memberis oval or elliptical in shape.
 18. The implant of claim 15, wherein theopening includes at least one flat portion adjacent at least one curvedportion.
 19. The implant of claim 15, wherein the implant is formed ofallograft bone.
 20. The implant of claim 15, wherein each of the firstlayer and second layer include a ridged surface formed thereon.